Effect of Ru on the activity of Co3O4 catalysts for chlorinated aromatics oxidationElectronic supplementary information (ESI) available. See DOI: 10.1039/c8cy01484a

Ru/Co 3 O 4 catalysts with a Ru content of 0-2 wt% were prepared by wet impregnation, and used in the catalytic combustion of chlorinated aromatic VOCs. Characterization by XRD, HRTEM, EXAFS, XPS, and H 2 -TPR showed that Co 3 O 4 existed in the form of a spinel structure. Some Ru species entered the octahedral sites of Co 3 O 4 to form Ru-O-Co, which significantly increased the surface oxygen, while the formation of RuO x clusters or nanoparticles on the surface promoted the reducibility of Co 3 O 4 . In the oxidation of chlorinated aromatics, Ru species can retard the negative effect of Cl species on the activity of Co 3 O 4 catalysts through modification in the chemical environments of surface oxygen and Cl species. The Ru/Co 3 O 4 catalysts presented good activity and selectivity, with a rate ( R Ru ) of 9.4-9.8 μmol m −2 min −1 under 1000 ppm 1,2-dichlorobenzene at 30 000 ml g −1 h −1 . The R Ru in wet feed over 2.0% Ru/Co 3 O 4 was increased by almost 100%, through the increase in availability of active surface oxygen from RuO x . A highly stable activity could be maintained for at least 50 h. In situ FT-IR showed that 1,2-DCB adsorbs on the Co 3+ /Co 2+ sites of Ru/Co 3 O 4 catalysts, and the formation of partial oxidation products involve the surface oxygen. For the Co 3 O 4 catalyst, surface active oxygen is almost not available during 1,2-DCB oxidation. A Ru/Co 3 O 4 catalyst with Ru-O-Co structure presented highly stable activity and selectivity in 1,2-DCB oxidation.